The present invention concerns the use of catalyst compositions comprising a Group VIII metal and a multidentate phosphonite ligand for olefinic hydrocyanation and isomerization processes.
Certain phosphonites have been used as a part of hydrocyanation catalyst systems. U.S. Pat. No. 5,817,850 discloses the use of a catalyst composition in hydroformylation and hydrocyanation reactions. WO9843935 discloses the use of certain phosphonite ligands as part of a catalyst system in a process for producing an aldehyde. WO9946044 relates to a hydroformylation process using phosphonite ligands as part of the catalyst system for hydroformylation reactions. U.S. Pat. No. 6,242,633 discloses a process for the production of nitriles using catalysts containing phosphonite ligands. Further, WO9964155 discloses use of catalysts containing phosphorous ligands in hydrocyanation reactions.
Despite the disclosure of various ligands in hydrocyanation and hydroformylation processes. Catalyst compositions comprising certain multidentate phosphonite ligands show effectiveness and/or higher performance and achieve improvements in rapidity, selectivity, efficiency or stability.
A hydrocyanation process, said process comprising: contacting an ethylenically unsaturated olefin compound with HCN in the presence of a catalyst composition, wherein said catalyst composition comprises a Group VIII metal and a phosphonite ligand wherein the ligand having a structure selected from the group consisting of: 
wherein the X groups are either the same or different unbridged organic aromatic groups as described in Formula I, wherein Q is a substituted or unsubstituted divalent aromatic or non aromatic hydrocarbon radical. The substituent on the Q groups is independently selected from the group consisting of C1 to C12 alkyl, cycloalkyl, alkoxy, alkylaryl, aryl, hetero aryl, cyano or
The use of a catalyst based on a ligand of structure II for the hydrocyanation and/or the positional isomerization or double bond isomerization of olefins.
The present invention describes a hydrocyanation process comprising: contacting an ethylenically unsaturated olefin compound with HCN in the presence of a catalyst composition, wherein the catalyst composition comprises a Group VIII metal and a phosphonite ligand having a structure selected from the group consisting of: 
wherein the X groups are either the same or different unbridged organic aromatic groups as described in Formula I, wherein Q is a substituted or unsubstituted divalent aromatic or non aromatic hydrocarbon radical; and when Q is substituted, the substituent on the Q group is independently selected from the group consisting of C1 to C12 alkyl, cycloalkyl, alkoxy, alkylaryl, aryl, hetero aryl, cyano.
Typical X for structure II include but are not limited to: 
The hydrocyanation process described herein may be carried out in the presence of a catalyst precursor composition comprising a Group VIII metal and at least one multidentate phosphonite ligand having a structure II I as described above and optionally a Lewis acid.
Generally, a Group VII metal or a compound thereof is combined with at least one of the ligand structure II to provide the catalyst. Among the Group VII metal compounds, nickel, cobalt, and palladium compounds are preferred for hydrocyanation catalysts. A nickel compound is more preferred, and a zero-valent nickel compound having a ligand that can be chemically displaced by the ligand structure of the present invention is the most preferred source of Group VIII metal or Group VIII metal compound.
Zero-valent nickel compounds that can be used for preparing the catalyst of the present invention are disclosed in the art. The preferred zero-valent nickel compounds are Ni(COD)2 (COD is 1,5-cyclooctadiene), Ni(P(O-o-C6H4CH3)3)3 and Ni{P(O-o-C6H4CH3)3}2(C2H4), all of which are known in the art.
The catalyst of the present invention is prepared by combining the zero-valent nickel compound with at least one molar equivalent of the ligand of structure II of the present invention in a ratio of nickel:bidentate ligand of 1:1. The ligand may be combined with nickel in a solvent, or preferably in the substrate medium. Suitable solvents include, but are not limited to, hydrocarbons such as benzene, xylene, or combinations thereof; ethers such as tetrahydrofuran (THF); nitriles such as acetonitrile, benzonitrile, adiponitrile, or combinations of two or more thereof. The unsaturated olefin used in the hydrocyanation process may itself serve as the solvent. The catalyst preparation may be done at room temperature, or at a temperature that is appropriate for the solvent being used, or the hydrocyanation process conditions.
Alternatively, divalent nickel compounds can be combined with a reducing agent, to serve as a source of zero-valent nickel in the reaction. Suitable divalent nickel compounds include compounds of the formula NiZ22 where Z2 is halide, carboxylate, or acetylacetonate. Suitable reducing agents include metal borohydrides, metal aluminum hydrides, metal alkyls, Li, Na, K, Zn or H2.
The divalent nickel compound is combined with the ligand structure II of the present invention in a suitable solvent, preferably the unsaturated olefin, in a ratio of 1:1, or preferably at least 2:1. The combination is then combined with a suitable reducing agent at room temperature, or at a temperature that is appropriate for the solvent being used, or the hydrocyanation process conditions being used. The resulting catalyst composition may be isolated, if desired.
Hydrocyanation Using Phosphorus-Containing Ligands of the Present Invention:
The catalyst compositions of the present invention may be used with or without a Lewis acid in the hydrocyanation of organic compounds. The hydrocyanation process comprises contacting, in the presence of the catalyst, an olefinic unsaturated organic compound with a hydrogen cyanide-containing fluid under conditions sufficient to produce a nitrile, wherein the catalyst comprises a Group VIII metal, at least one of the ligands described above, and optionally a Lewis acid as a promoter. As used herein, the term xe2x80x9cfluidxe2x80x9d means gas, a liquid, or a combination of these. Any fluid containing about 1 to 100% HCN can be used.
A particularly significant use of the ligands of the present invention is in the hydrocyanation of olefins. In such a process, an olefinic compound such as a diolefinic compound can be converted to a nitrile or a dinitrile, or a combination thereof. The hydrocyanation process can be carried out, for example, by charging a suitable vessel with an olefin, catalyst composition, and solvent, if used, to form a reaction mixture. Hydrogen cyanide can be combined initially with other components to form the mixture. However, it is preferred that HCN be added slowly to the mixture after other components have been combined. Hydrogen cyanide can be delivered as a liquid or as a vapor to the vessel. As an alternative, a cyanohydrin can be used as the source of HCN. See, for example, U.S. Pat. No. 3,655,723, incorporated herein by reference.
Another suitable technique is to charge the vessel with the catalyst and the solvent (if any) to be used, and feed both the unsaturated compound and the HCN slowly to the reaction mixture.
The molar ratio of ethylenically unsaturated olefin compound to catalyst can be varied from about 10:1 to about 10000:1. The molar ratio of HCN to catalyst generally is varied from about 10:1 to 100,000:1, preferably 100:1 to 5,000:1, for a batch operation. In a continuous operation, such as when using a fixed bed catalyst type of operation, a higher proportion of catalyst can be used such as a molar ratio of about 5:1 to about 100,000:1, and preferably about 100:1 to about 5,000:1, HCN to catalyst.
Preferably, the reaction mixture is agitated, for example, by stirring or shaking. The reaction product can be recovered by conventional techniques such as distillation. The process can be run either batchwise or continuously.
The hydrocyanation can be carried out with or without a solvent. The solvent, if used, can be liquid at the reaction temperature and pressure and inert towards the olefin and the catalyst. Suitable solvents include, but are not limited to, hydrocarbons such as benzene, xylene, or combinations thereof; ethers such as tetrahydrofuran (THF); nitriles such as acetonitrile, benzonitrile, adiponitrile, or combinations of two or more thereof. The unsaturated olefin to be hydrocyanated can itself serve as the solvent. Hydrocyanation can also be carried out in the gas phase.
The exact temperature is dependent to a certain extent on the particular catalyst being used, the particular olefin being used and the desired reaction rate. Normally, temperatures of from about xe2x88x9225xc2x0 C. to about 200xc2x0 C. can be used with the range of 0xc2x0 C. to 150xc2x0 C. being preferred.
Atmospheric pressure is suitable for carrying out the reaction, and hence pressures of from about 0.05 to 10 atmospheres (50.6 to 1013 kPa) are preferred. Higher pressures, up to 10,000 kPa or more, can be used, if desired, but any benefit that may be obtained thereby would probably not justify the increased cost of such operations.
The time required can be in the range of from a few seconds to many hours (such as 2 seconds to 24 hours), depending on the particular conditions and method of operation.
The ethylenically unsaturated olefin compound is acyclic and aliphatic, or a combination of two or more ethylenically unsaturated olefin compounds that each are acyclic and aliphatic. A non-limiting example of these compounds is shown in Formula IV, and the corresponding nitrile compound produced by the hydrocynation process is shown by Formula V, respectively. 
The ethylenically unsaturated olefin has 2 to about 30 carbon atoms per molecule and has the formula selected from the group consisting of R3CHxe2x95x90CHxe2x80x94CHxe2x95x90CR4, CHxe2x95x90CHxe2x80x94(CH2)qxe2x80x94R5, CH3xe2x80x94(CH2)nxe2x80x94CHxe2x95x90CHxe2x80x94(CH2)qxe2x80x94R6, and combinations of two or more thereof, wherein R3 and R4 are each independently H, C1 to C3 alkyl, or combinations thereof; R5 is H, CN, CO2R8, perfluoroalkyl having 1 to about 20 carbon atoms; n is an integer of 0 to 12; q is an integer of 0 to 12 when R6 is H or perfluoroalkyl, and q is an integer of 1 to 12 when R6 is CO2R7, CN; and R7 is C1 to C12 alkyl or cycloalkyl, C6 to C20 aryl, or combinations thereof.
Examples of suitable olefins include ethylenically unsaturated compounds such as ethylene, propylene, 1-butene, 2-pentene, 2-hexene, and combinations of two or more thereof; non-conjugated diethenically unsaturated compounds such as allene, substituted ethenically unsaturated compounds such as 3-pentenenitrile, 4-pentenenitrile, methyl pent-3-enoate, and combinations of two or more thereof; and ethenically unsaturated compounds having perfluoroalkyl substituents such as, for example, CbF2b+1, where b is an integer of up to 20. Preferred olefins are linear alkenes, linear alkenenitriles, linear alkenoates, perfluoroalkyl ethylenes, and combinations of two or more thereof. Most preferred olefins include 3- and 4-pentenenitrile, alkyl 3-, and 4-pentenoates, and CbF2b+1CHxe2x95x90CH2 (where b is 1 to 12), and combinations of two or more thereof. 3-Pentenenitrile and 4-pentenenitrile are the most preferred.
The preferred products are terminal alkane nitriles, linear dicyanoalkylenes, linear aliphatic cyanoesters, 3-(perfluoroalkyl)propionitrile, and combinations of two or more thereof. Most preferred products are adiponitrile, alkyl 5-cyanovalerate, CbF2b+1CH2CH2CN, where b is 1 to 12, and combinations of two or more thereof.
The process of this invention can be carried out in the presence of one or more Lewis acid promoters to affect both the activity and the selectivity of the catalyst system. The promoter may comprise an inorganic or organometallic compound in which the cation is selected from the group consisting of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, copper, zinc, boron, aluminum, yttrium, zirconium, niobium, molybdenum, cadmium, rhenium and tin. Examples include, but are not limited to, ZnBr2, ZnI2, ZnCl2, ZnSO4, CuCl2, CuCl, Cu(O3SCF3)2, CoCl2, CoI2, FeI2, FeCl3, FeCl2, FeCl2(THF)2, TiCl2, TiCl4(THF)2, MnCl2, ScCl3, AlCl3, (C8H17)AlCl2, (C8H17)2AlCl, (iso-C4Hg)2AlCl, Ph2AlCl, PhAlCl2, ReCl5, ZrCl4, NbCl5, VCl3, CrCl2, MoCl5, YCl3, CdCl2, LaCl3, Er(O3SCF3)3, Yb(O2CCF3)3, SmCl3, B(C6H5)3, TaCl5. Suitable promoters known in the art. These include metal salts, such as ZnCl2, CoI2, and SnCl2, and organometallic compounds (such as R8AlCl2, R8SnO3SCF3, and R8B, where R8 is an alkyl or aryl group). U.S. Pat. No. 4,874,884 (incorporated herein by reference) describes how synergistic combinations of promoters can be chosen to increase the catalytic activity of the catalyst system. Preferred promoters include CdCl2, FeCl2, ZnCl2, B(C6H5)3, and (C6H5)3Sn(CF3SO3), CH3C6H5SO3, or (C6H5)3BCN. The mole ratio of promoter to Group VIII metal present in the reaction can be within the range of about 1:16 to about 50:1.
Hydrocyanation can also be carried out with a conjugated ethylenically unsaturated olefin having from 4-15 carbon atoms, preferably 4 to 10 carbon atoms. With conjugated olefins, a Lewis Acid promoter is optional. Examples of conjugated olefins containing from about 4 to about 15 carbon atoms are 1,3-butadiene, cis and trans-2,4-hexadienes, cis and trans-1,3-pentadienes, and combinations of two or more thereof. Butadiene is especially preferred.
The following Formulae VI and VII illustrate some suitable starting conjugated olefins. The products of the hydrocyanation process, as described herein, of 1,3-butadiene are represented in Formulas VIII, IX, and X:
CH2xe2x95x90CHxe2x80x94CHxe2x95x90CH2xe2x80x83xe2x80x83VI
R9CHxe2x95x90CHxe2x80x94CHxe2x95x90CHR10xe2x80x83xe2x80x83VII
(1,3-butadiene)
wherein each one of R9 and R10, independently, is H or a C1 to C3 alkyl; 
in which 3PN denotes 3-pentenenitrile, 4PN is 4-pentenenitrile, and 2M3BN is 2-methyl-3-butenenitrile.
The reaction of a conjugated olefin and a HCN-containing fluid can be carried out in the same manner as that described above in relation to monoethenically unsaturated compounds.
The catalyst compositions of the present invention may also be used in the isomerization of allylic nitrites. The catalyst composition is combined with the allylic nitrile in a vessel and the isomerization process is carried at from 0 degrees C. to 150 degrees C., and preferably from 80 degrees C. to 120 degrees C. A solvent may be used. Examples of a suitable solvent include but are not limited to, hydrocarbons such as benzene, xylene, or combinations thereof; ethers such as tetrahydrofuran (THF); nitrites such as acetonitrile, benzonitrile, adiponitrile, or combinations of two or more thereof.